Sep 12, 2025
The period between the 11th and 13th of September had a relatively unique meteorological setup for western Colorado and eastern Utah. A potent closed low was located over Southern California, and a ridge of high pressure was located to our southeast, directing a rich plume of monsoonal moisture northward through the Four Corners. Mixing ratios in this plume of moisture were more than high enough to not only help form strong to severe thunderstorms, but also to produce flash flooding and debris f
Source: NOAA National Weather Service Storm Events Database (event 1295705). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Grand County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.